Run time during cold snap

gyrfalcon

My big boiler normally runs approximately 7 minutes, give or take, depending on outside temps and which zones are calling .  Temps are dropping fast here in South central Indiana.  9 deg F right now. Negative digits by morning.  I’ll be curious to observe my boiler’s operation during this winter weather.  

Big Ed_4

If it was a properly sized boiler it run constantly on the coldest day of the year ,and you can hold 65* up stairs ..

hot_rod

Sounds like sounds like you are getting close to design day condition. Ideally at design temperature it would run non stop

Jersey2

I am curious about mine too and am monitoring it, since this is its first winter. I named my boiler Godzilla lol. Thus far, if zone 2 runs by itself it runs about 18 minutes, and zone 1 by itself it runs about 30 minutes, and if for the water tank only it runs about 8 minutes, and then doesn't run for hours. The lows are in the high 20's and highs in the high 30's but it supposed to get much colder out soon. I keep the thermostats on the cool side to conserve energy.

gyrfalcon

Design day is 5deg.  Boiler is rated 100k input 82k output.  Last combustion test showed 78-80%.  Heat loss calc approximately 30-50k .  Baseboard lengths at 600 btu per foot = 39k 

 Zone stats are set at 64. East side zone of house is at 60 degrees- last cycle 12.7 minutes .  West side zone 62 degrees- last cycle 7.05 seconds 

Weather app shows -9 outside.   

Temp in sunroom is 68(not a lot of insulation and definitely some drafts. 12k Mitsu hyper heat mini split is set to 72. 

We have not turned on central air handler electric strips nor made a wood fire in the Jotul. 

But… work may be delayed or canceled and I have seasoned oak ready to load and burn!!!

WMno57

Greetings fellow Hoosier. Negative 9 here in NW Indiana. Ran my boiler for two hours straight this AM. Got the house up from 65 to 67. Fingers crossed the power stays on.

hot_rod

gyrfalcon said:

Design day is 5deg.  Boiler is rated 100k input 82k output.  Last combustion test showed 78-80%.  Heat loss calc approximately 30-50k .  Baseboard lengths at 600 btu per foot = 39k 

 Zone stats are set at 64. East side zone of house is at 60 degrees- last cycle 12.7 minutes .  West side zone 62 degrees- last cycle 7.05 seconds 

Weather app shows -9 outside.   

Temp in sunroom is 68(not a lot of insulation and definitely some drafts. 12k Mitsu hyper heat mini split is set to 72. 

We have not turned on central air handler electric strips nor made a wood fire in the Jotul. 

But… work may be delayed or canceled and I have seasoned oak ready to load and burn!!!

Sounds like you system will keep you comfortable.
I’d guess more like 500- 550 btu/ ft from standard fin tube, unless you are supplying 190F or higher. So your boiler is close to 3 time the size of the heat emitter connected to it. Which explains the reality it’s short cycles at or near design condition.
65’ of fin tube matches the load nicely @ 39K
Sounds like the mini split contributes also?

gyrfalcon

@WMno57, Salutations and good tidings to you.  My wife’s family lives east of your area, near lake Wawasee, Indiana’s largest natural lake. Stay safe and warm!  Is your boiler from Michigan City? 

@hot_rod, you are correct, on all fronts.  This is the first winter with the Mitsubishi,  I like it. The only problem thus far is we had a mysterious leak earlier this week.  The installer is coming back for a more thorough Nitro test.  I hope it holds up!!  

 

We have considered replacing the 1.5 ton American Standard AC with a ducted Mitsubishi and keep the old oversized boiler as back up as temps drop. 

Or. Replace current boiler with smaller Utica  cast (keep current AC)  or a Lochinvar mod con. 

And of course ,  do we keep the standard water heater ?  Replace with indirect? 

So many options,  I’m just thankful all my equipment is working!!!

gyrfalcon

Btw,  I’m usually a fan of simple design and cost and can’t stand buyer’s remorse!!  

hot_rod

gyrfalcon said:

Btw,  I’m usually a fan of simple design and cost and can’t stand buyer’s remorse!!  

Throw in the uncertainty of fuel availability and cost and the decision gets even more complex.

gyrfalcon

Right, @hot_rod!  Either way, I’m buying something-  LP or electric.  How much for how much??

Hot_water_fan

We have considered replacing the 1.5 ton American Standard AC with a ducted Mitsubishi and keep the old oversized boiler as back up as temps drop.

An easy swap, either soon or at the end-of-life for the American Standard. I have the ducted Mitsubishi hyper heat but there are other, cheaper heat pumps out there. With the boiler backup, it's less important to have the low ambient temperature capacity.

gyrfalcon

One thought, put the American Standard in the garage!  

WMno57

@gyrfalcon I'm about a half an hour south of Michigan City, IN and yes I think my Weil-McLain boiler was made there in their foundry somewhere between about 1946 and 1950. Someday I would like to visit their facility.

Imagine buying something today and having it still working in the year 2100!
Instead of an indirect for domestic water heating you may want to consider either an electric resistance or heat pump water heater. My electric co-op offers rebates for both, and I also get 5 bucks off each bill for having the electric water heater.

STEVEusaPA

Probably almost all of us hydronic fans stare at their boilers on design day, noting run times, and maybe secretly hoping it doesn’t shut off, lol.

gyrfalcon

@WMno57, I have a Chambers gas range from the 50s , I think. It was made in Shelbyville.